Mechanical Engineering Commons^™

Modeling Of The Size Effects On The Behavior Of Metals In Microscale Deformation Processes, Gap-Yong Kim, Jun Ni, Muammer Koc

Gap-Yong Kim

For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/mesoscale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the “grain size” effect, and the other is the “feature/specimen size” effect. This study investigated the feature/specimen size effect and introduced a scaling model which combined both feature/specimen and grain size effects. Predicted size effects were compared with three separate experiments obtained from previous research: a simple compression with a round specimen, a simple tension with a round specimen, and a simple tension in …

Effect Of Chromium–Gold And Titanium–Titanium Nitride–Platinum–Gold Metallization On Wire/Ribbon Bondability, Jianbiao Pan, Robert M. Pafchek, Frank F. Judd, Jason B. Baxter

Industrial and Manufacturing Engineering

Gold metallization on wafer substrates for wire/ribbon bond applications requires good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr-Au and Ti-TiN-Pt-Au metallization systems for an optoelectronic application. Both Chromium and Titanium are used to promote adhesion between semiconductor substrates and sputtered gold films. However, both will be oxidized if they diffuse to the gold surface and result in the degradation of the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr-Au and Ti-TiN-Pt-Au, annealing, and CAN etch processes, on …

An Evaluation Of Attributes And Competencies For Manufacturing Engineering Technology Graduates, Loni S. Williamson

Theses and Dissertations

The purpose of this study is to determine the required attributes and competencies required for a graduate from a manufacturing engineering technology baccalaureate program. A document called “Competencies of Manufacturing Engineering Technology Graduates” was compiled in October 2004. This document lists twelve attributes thought to be important for MET graduates: Leadership, Professionalism, Creativity and Problem Solving, Management, Materials, Processes, Quality, Systems, Design, Communication, Safety and Environmental Issues, and Global Awareness. Under each attribute is a list of five to seven competencies creating a total of seventy-three competencies for graduates of an MET baccalaureate program. This list of attributes and competencies …

Modeling Of The Semi-Solid Material Behavior And Analysis Of Micro-/Mesoscale Feature Forming, Gap-Yong Kim, Muammer Koc, Rhet Mayor, Jun Ni

Gap-Yong Kim

One of the major challenges in simulation of semi-solid forming is characterizing the complex behavior of a material that consists of both solid and liquid phases. In this study, a material model for an A356 alloy in a semi-solid state has been developed for high solid fractions (>0.6) and implemented into a finite element simulation tool to investigate the micro-/mesoscale feature formation during the forming process. Compared to previous stress models, which are limited to expressing the stress dependency on only the strain rate and the temperature (or the solid fraction), the proposed stress model adds the capability of …

An Experimental Investigation On Semi-Solid Forming Of Micro/Meso-Scale Features, Gap-Yong Kim, Jun Ni, Rhett Mayor, Heesool Kim

Gap-Yong Kim

The potentials of semi-solid forming technology have generated much interest regarding its application in micromanufacturing. This study investigates the feasibility of using semi-solid forming technology to produce parts with micro/meso features. An experimental setup has been developed to study the effects of die/punch temperature, initial solid fraction, punch speed, and workpiece shape on the semi-solid forming process. A part has been produced for a microreactor application and has been analyzed with an optical measurement system for feature formation. The results indicated complex interaction among the process parameters and the material flow, which affected the final pin formation. The punch temperature …

Investigation Of The Lead-Free Solder Joint Shear Performance, James Webster, Jianbiao Pan, Brian J. Toleno

Industrial and Manufacturing Engineering

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The purpose of this study is to investigate the effects of reflow profile and thermal shock on the shear performance of eutectic SnPb (SnPb) and Sn3.0Ag0.5Cu (SAC305) solder joints. Test boards were assembled with four different sized surface mount chip resistors (1206, 0805, 0603 and 0402). Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb were developed with three levels of peak temperature (12ºC, 22ºC, and 32ºC above solder liquidus temperature, or 230ºC, 240ºC, and 250ºC for SAC …

Tribo-Surface Characteristics Of Al-B4c And Al-Sic Composites Worn Under Different Contact Pressures, Haseeb Asma

Haseeb ASMA

Tribo-surface characteristics of two aluminium metal matrix composites (Al-MMC) of compositions Al-13 vol%B4C and Al-13 vol%SiC sliding against a commercial phenolic brake pad have been investigated under dry conditions. The wear tests were carried out using a pin-on-disc type apparatus at a linear speed of 1.62 ms(-1) under contact pressures ranging from 0.75 to 3.00 MPa. The coefficient of friction was recorded on line. Wear rates were calculated from mass loss measurements. Scanning electron microscope equipped with energy dispersive X-ray spectroscopy was used to examine the tribo-surface. It is found that wear rate of both composites increases with increasing contact …

Modeling Of The Effects Of Athermal Flow Strength And Activation Energy For Dislocation Glide An The Nanoindentation Creep Of Nickel Thin Film At Room Temperature, Haseeb Asma

Haseeb ASMA

Nanoindentation creep behaviour of nickel at room temperature has been modeled based on the obstacle-controlled dislocation glide mechanism. Using the model, the effects of two important materials parameters viz. the activation free energy required by dislocation to overcome an obstacle without any aid from external stress, Delta F and the athermal flow strength, tau(0), which is the flow strength of solids at 0 K are systematically studied. It has been found that Delta F plays a dominant role in room temperature creep properties of nickel. The role of Delta F is particularly dominant in determining the time dependent deformation. On …

Estimation Of Liquidus Temperature When Snagcu Bga/Csp Components Are Soldered With Snpb Paste, Jianbiao Pan

Industrial and Manufacturing Engineering

Recently, the soldering of lead-free components with SnPb paste, or lead-free backward compatibility, is becoming a hot topic. One of the major challenges in backward compatibility assembly is the development of a right reflow profile for the soldering of SnAgCu Ball Grid Array (BGA)/Chip Scale Package (CSP) components with SnPb paste. If the SnAgCu reflow profile is used, the reflow temperature may be too high for other SnPb components in the same board during assembly according to the component rating per IPC/JEDEC J-STD-020C. In addition, the flux in SnPb solder paste may not function properly in such a high reflow …

Numerical Simulation And Prediction Of Dilution During Laser Deposition, Zhiqiang Fan, Anand Jambunathan, Todd E. Sparks, Jianzhong Ruan, Yu Yang, Yaxin Bao, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The laser additive manufacturing technique of laser deposition allows quick fabrication of fully-dense metallic components directly from Computer Aided Design (CAD) solid models. The applications of laser deposition include rapid prototyping, rapid tooling and part refurbishment. The development of an accurate predictive model for laser deposition is extremely complicated due to the multitude of process parameters and materials properties involved. In this work, a heat transfer and fluid flow model is developed. The model is used to predict dilution under varying process parameters for deposits of Ti-6Al-4V. Experimental validation of the predicted dilution is presented. The laser used is a …

Effect Of Structured Laser Pulses On Grain Growth In H13 Tool Steel, Todd E. Sparks, Jianzhong Ruan, Zhiqiang Fan, Yaxin Bao, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In metal solidification. the cooling rate is an important factor in determining the resultant grain structure of the material. The paper discusses the results of a feasibility study done to determine whether a laser pulse scheme can be designed to affect, and eventually control, the resultant microstructure of the deposited material. A factorial experimental approach is applied to determine the significant parameters affecting grain size and orientation. Parameters investigated include maximum pulse power, pulse frequency, pulse shape, and material feed rate. Particular attention is given to parameter combinations that can cause grain growth through the layer boundaries of the deposited …

Applications Of A Hybrid Manufacturing Process For Fabrication And Repair Of Metallic Structures, Frank W. Liou, Kevin P. Slattery, Mary Kinsella, Joseph William Newkirk, Hsin-Nan Chou, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Since its appearance, rapid prototyping technology has been of interest to various industries that are looking for a process to produce/build a part directly from a CAD model in a short time. Among them, the direct metal deposition process is the only process which directly manufactures a fully dense metal part without intermediate steps. However, challenges of the direct metal deposition process include building overhang structures, producing precision surfaces, and making parts with complex structures. Coupled between the additive and the subtractive processes into a single workstation, the integrated process, or hybrid process, can produce a metal part with machining …

Automation Of A Hybrid Manufacturing System Through Tight Integration Of Software And Sensor Feedback, Jacquelyn K. Stroble, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a framework for the automation of the Laser Aided Manufacturing Process (LAMP) lab at the University of Missouri-Rolla. The groundwork for the proposed system involves the integration of the LabVIEW software package and a PXI-8195 real time controller with several sensors and actuators. The incorporation of all key control parameters into one virtual instrument will help achieve the goal of an automated hybrid system. To achieve this goal, a five-phase plan, which will be further discussed in the paper, has been developed. The first phase of this plan, which includes the deposition of a thin walled structure …

Determination Of Transformation Matrix In A Hybrid Multi-Axis Laser-Aided Manufacturing System And Its Practical Implementation, Ajay Panackal Padathu Vijayan, Todd E. Sparks, Jianzhong Ruan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Laser Aided Manufacturing Process (LAMP) is a multi-axis hybrid manufacturing process comprised of both an additive process, laser deposition, and a subtractive process, CNC machining. Determination of transformation matrix is one of the most important tasks to bridge the gap between process planning (software) and real deposition/machining process. The first part of the paper discusses an algorithm for computing the position of point/points in three-dimensional space, using homogenous transformation matrices. The second part of the paper discusses about how the algorithm was used in practice to build 3-D parts and part-repair using hybrid manufacturing process.

Comparison Of Thermal Properties Of Laser Deposition And Traditional Welding Process Via Thermal Diffusivity Measurement, Yu Yang, Omoghene Osaze Obahor, Yaxin Bao, Todd E. Sparks, Jianzhong Ruan, Jacquelyn K. Stroble, Robert G. Landers, Joseph William Newkirk, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser deposition is an effective process for mold and die repair. In order to improve the part repair quality, the process impact on thermal diffusivity and thermal conductivity needs to be understood for laser deposited, welded and virgin H13. In this paper, H13 tool steel samples were made by laser deposition, welding and virgin H13 and then cut into pieces. Experiments were conducted to investigate the thermal diffusivity and conductivity. A laser flash method is used to test these samples. The future work and opportunities are also summarized.

Evaluation Of Mechanical Properties And Microstructure For Laser Deposition Process And Welding Process, Yaxin Bao, Jianzhong Ruan, Todd E. Sparks, Jambunathan Anand, Joseph William Newkirk, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Aided Manufacturing Process (LAMP) can be applied to repair steel die/molds which are currently repaired using traditional welding process in industry. In order to fully understand the advantages of laser deposition repair process over traditional welded-repair process, the mechanical properties such as tensile strength and hardness of H13 tool steel samples produced by these two processes were investigated. The microstructure and fracture surface of the samples were analyzed using optical microscope and SEM (Scanning Electron Microscope). Moreover, depositions on substrates with different shapes were studied to evaluate the performance of LAMP on damaged parts with complicated geometric shape.

Three Dimensional Die Repair Using A Hybrid Manufacturing System, Lan Ren, Ajay Panackal Padathu, Jianzhong Ruan, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A dramatic reduction in the cost, energy and time can be achieved by pursuing part repairing especially for die industry. In this paper, repairing process development was carried out by a hybrid manufacturing system aiming at the prevalent kinds of die core damages which is worn-out or corroded surface. Surface patches pattern is used for generating tool path to repair the damaged faces. A user-friendly software tool was developed to facilitate the users. 3D repairing technology was also integrated which ensures the alignment when more than one damages need to be repaired without reloading the part. Realization of 3D surface …

A Review Of Layer Based Manufacturing Processes For Metals, Jianzhong Ruan, Todd E. Sparks, Zhiqiang Fan, Jacquelyn K. Stroble, Ajay Panackal, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The metal layered manufacturing processes have provided industries with a fast method to build functional parts directly from CAD models. This paper compares current metal layered manufacturing technologies from including powder based metal deposition, selective laser sinstering (SLS), wire feed deposition etc. The characteristics of each process, including its industrial applications, advantages/disadvantages, costs etc are discussed. In addition, the comparison between each process in terms of build rate, suitable metal etc. is presented in this paper.

Freeform Extrusion Of High Solids Loading Ceramic Slurries, Part I: Extrusion Process Modeling, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A novel, solid freeform fabrication method has been developed for the manufacture of ceramic-based components in an environmentally friendly fashion. The method is based on the extrusion of ceramic slurries using water as the binding media. Aluminum oxide (Al₂O₃) is currently being used as the part material and solids loading as high as 60 vol. % has been achieved. This paper describes a novel manufacturing machine that has been developed for the extrusion of high solids loading ceramic slurries. A critical component of the machine is the deposition system, which consists of a syringe, a plunger, …

Freeform Extrusion Of High Solids Loading Ceramic Slurries, Part Ii: Extrusion Process Control, Michael S. Mason, Tieshu Huang, Robert G. Landers, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Part I of this paper provided a detailed description of a novel fabrication machine for high solids loading ceramic slurry extrusion processes and presented an empirical model of the ceramic extrusion process, viewing ram velocity as the input and extrusion force as the output. A constant extrusion force is desirable as it correlates with a constant material deposition rate and, thus, good part quality. The experimental results used to construct the model demonstrated that a constant ram velocity will not necessarily produce a constant extrusion force. In some instances the extrusion force increased until ram motor skipping occurred, and process …

Freeze-Spray Processing Of Layered Ceramic Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Thermal gradients and associated stresses are critical in designing with ceramic composites having low thermal conductivity. In order to reduce the stresses from thermal gradients, compositional gradients are employed in designing of composite structures. This study addresses development of freeze-spray process to fabricate layered ceramic structures with controlled layer thickness and microstructural development. The composites were processed by spraying of ceramic slurries with low binder content and relatively high solids loadings (up to 40 vol%) on a cooled substrate. The frozen parts were freeze-dried and sintered at elevated temperatures. The relationship between microstructural development and thermal expansion behavior of Al …

Contractor Variability In Construction Of Cement Treated Base Layers, Maile Anne Rogers

Theses and Dissertations

The primary purposes of this research were to identify construction factors most correlated to specific mechanical properties of cement-treated base (CTB) layers and to determine which construction factors exhibit comparatively high variability within individual construction sections of the two pavement reconstruction projects included in this study. In addition, differences between construction sections tested in this research were evaluated. The research focused on the construction of CTB layers in two pavement reconstruction projects in northern Utah, one along Interstate 84 (I-84) near Morgan and one along U.S. Highway 91 (US-91) near Richmond. The significant predictor variables associated with California bearing ratio …

A Solution For Commodity Field Hauling With Self-Unloading Semi-Trailers, Lee Pagens Wilkerson

Theses and Dissertations

Commodity hauling of bulk goods is a growing enterprise that has expanded from hauling agricultural products to hauling many other bulk products. Commodity trailers are used to haul agricultural products from storage facilities to processing plants. These trailers are designed for highway use but are frequently required to work in field conditions as well. In many cases this environment overstresses these trailers and results in permanent irreparable damage. In addition to the structural problems of these trailers, the current systems for unloading the bulk produce from these trailers have serious inadequacies. While functional, the currently used chain and non-chain driven …

A Stochastic Production Cost Model For Remanufacturing Systems, Gaurang S. Patel

Theses and Dissertations - UTB/UTPA

Growing environmental concern throughout this decade coupled with enforced legislation, customer expectations and economic incentives have forced increasing number of manufacturers to take back their products from end user. Managing this reverse flow of products is called reverse logistics. The stochastic nature of returned products complicates the production planning for remanufacturing systems in reverse logistics. In this thesis a stochastic production cost model, considering various costs associated under different situations for remanufacturing systems of returned products is developed. A search algorithm method is recommended to determine optimal production run size, production rate and space for remanufacturing systems in reverse logistics. …

A Comparative Study Of Various Loss Functions In The Economic Tolerance Design, Jehnan Pan, Jianbiao Pan

Industrial and Manufacturing Engineering

Engineering tolerance design plays an important role in modern manufacturing. In this paper, the Kapur's model was modified so that the economic specification limits for both symmetric and asymmetric losses can be established. Three different loss functions: (1) Taguchi's quadratic loss function; (2) Inverted Normal Loss Function; (3) Revised Inverted Normal Loss Function are compared in the economic tolerance design. The relationships between the three loss functions and process capability indices for symmetric tolerance are established. The results suggest that the revised inverted normal loss function be used in determination of economic specification limits.

Plotting A Bright Future For Manufacturing Education: Results Of A Brainstorming Session, Daniel Waldorf, Sema E. Alptekin, Robert Bjurman

Industrial and Manufacturing Engineering

Manufacturing industries worldwide have undergone dramatic changes in recent years and now demand more from graduating manufacturing engineers. The effects of globalization have forever changed the parameters for success in manufacturing. Our educational institutions must respond to these changes with innovation. That agenda formed the basis for a special SME/CIRP international conference on manufacturing engineering education called “Looking Forward: Innovations in Manufacturing Engineering Education,” held in San Luis Obispo, California, June 22-25, 2005. At the meeting, manufacturing education professionals from around the world came together to share their own innovative ideas and to brainstorm ways to shape the future of …

Exchange Faculty Perspectives On International Collaborations, Donal Mchale

Conference Papers

The main purpose of the paper is to document key issues in developing successful transatlantic faculty exchanges and to document perspectives and key learnings’ emanating from the development and implementation of an international exchange process.

Automated Manipulation For The Lotus Filament Winding Process, Jeffrey V. Anderson

Theses and Dissertations

The filament-winding process produces quality consistent composite parts for many industries. Filament winding allows for consistent quality parts by automating the winding process. A recent development of filament winding is the Lotus process. The Lotus process reverses conventional filament winding by leaving the mandrel stationary and winding composite fiber around the mandrel. The automated Lotus filament-winding machine is controlled by four-axis control manipulating the Lotus ring around a fixed mandrel. This allows Lotus filament winding to wind parts that do not have a linear axis. Lotus filament winding is in its early stages of development. As a second step in …

Processing Model For Tungsten Powders And Extention To Nanoscale Size Range, Randall M. German, J. Ma, X. Wang, E. Olevsky

Industrial and Manufacturing Engineering

Nanoscale tungsten powders promise access to very hard, strong and wear resistant materials via the press–sinter route. A small particle size changes the response during sintering, requiring lower temperatures and shorter times to attain dense but small grain size structures. On the other hand, oxide reduction and impurity evaporation favour high sintering temperatures and long hold times. Accordingly, press–sinter processing encounters conflicting constraints when applied to small particles. Presented here is an analysis of press–sinter tungsten particle processing to isolate conditions that balance the temperature and size dependent effects. The calculations are pinned by existing data. Opportunities are identified for …

The Effect Of Reflow Profile On Snpb And Snagcu Solder Joint Shear Strength, Jianbiao Pan, Brian J. Toleno, Tzu-Chien Chou, Wesley J. Dee

Industrial and Manufacturing Engineering

Purpose –The purpose of this work is to study the effect of the reflow peak temperature and time above liquidus on both SnPb and SnAgCu solder joint shear strength.

Design/methodology/approach –Nine reflow profiles for Sn3.0Ag0.5Cu and nine reflow profiles for Sn37Pb have been developed with three levels of peak temperature (230°C, 240°C, and 250°C for Sn3.0Ag0.5Cu; and 195°C, 205°C, and 215°C for Sn37Pb) and three levels of time above solder liquidus temperature (30, 60, and 90 s). The shear force data of four different sizes of chip resistors (1206, 0805, 0603, and 0402) are compared across the different …